BOISE - A federal judge ruled Monday that the U.S. Bureau of Land Management once again violated federal laws when it issued grazing permits instead of analyzing how grazing could harm sage grouse in four allotments in south-central Idaho.

U.S. District Judge B. Lynn Winmill found that the BLM failed to consider stopping grazing in any of the proposed management plans in the agency's Burley Field Office.

The BLM failed to analyze existing sage grouse habitat conditions in the four allotments, Winmill wrote, which he described as "particularly troubling" because the species is a candidate for listing under the Endangered Species Act.

He also wrote that the four allotments are degraded by livestock grazing.

"In this case, the (environmental assessment) failed to identify reasonable alternatives," the ruling said. "The existing grazing levels were contributing to sage grouse habitat degradation and yet the EA evaluated no alternative that would have reduced grazing levels and/or increased restrictions on grazing."

The decision is round two of a lawsuit led by conservation group Western Watersheds Project that is challenging nearly 600 BLM grazing allotments spread across southern Idaho.

"It is very clear the BLM especially is not doing what's right for sage grouse and not reversing the decline of sage grouse habitat," said Ken Cole, National Environmental Policy Act coordinator at the Boise office of Western Watersheds Project. "We have declining sage grouse populations. We didn't get there because of oil and gas, we got there because of grazing. Grazing is the biggest impact on sage grouse, at least in Idaho and many other places."

Winmill agreed that the BLM is allowed to automatically renew grazing permits without conducting lengthy environmental reviews. However, it must still comply with federal laws requiring the agency to consider ongoing rangeland degradation and observe the Fundamental of Rangeland Health regulations during allotment renewal.

The BLM is currently reviewing the decision, agency spokeswoman Jessica Gardetto said.

"The BLM wants to manage livestock consistent with our standards and our multiple-use mission," she said. "We'll follow his decision accordingly."

Sage grouse are a chicken-sized bird known for its elaborate mating display. Besides Idaho, the bird is found in 10 other Western states.